In reply to 1poundSOCKS:
I think that renting the car can be pretty cheap in this period of time. I was renting car in the same time of the year twice, and the cheapest option was around 5 euro or pounds, per day, so for two weeks it can be as litlle as 100 euro/pounds. It was 4 and 5 years ago when i was there, but i guess the price didnt change a lot. This period is pretty dead for tourism so rental companys will be happy to give You a car for silly money.
If You take the car then 2 hours after landing You can be in el chorro. Never used public transport option but i guess it takes a bit more time.
There is a supermarket few kilometres from el. Chorro so having a car is a big advantage if it comes to choosing Your food and its probaly cheaper then in the village shop.
In the rest day a good option can be a trip to hot springs, around 150km from el chorro but worth going. Its cool to go into warm water when the temp outside is low. I dont remember where they were but google will help You. I didnt have precise info about them but i found them quite easilly.
Last but not least, car gives some safety to Your equipment. I read and ive heard from people that some climbers were robbed, especcialy when they stayed wild camping. I was wild camping next to small church and i didnt have any problem but i had a car.
I dont work for rental companys but i strongly recommend renting a car. Ont the cold and rainy days or just at rest days, there was nothing to do in el chorro. Only one pub, small internet cafe at camp side, and small shop with food, plus one climbing shop with grumpy owner and a litlle of gear to choose from. At least in 2012.